Problem No. 1 in the practical utilization of solar energy is that the sun sets every evening, while the energy requirements of mankind continue round the clock. As a solution to this problem I offer a solar powered gas generation process, covered by U.S. Pat. No. 4,080,271, wherein solar power is utilized to generate an electrical potential, which in turn is applied to the electrolytic separation of hydrogen from sea water. Hydrogen is the ecologically perfect fuel, or it can be utilized in the manufacture of propane, which is, everything considered, the practically preferable fuel. Propane, the fuel of the future, can be utilized round the clock in every application in which fuel is consumed.
Problem No. 2 is that the solar heat coming to the earth is too much attenuated to be of practical utility in the generation of power. It must be concentrated in order to become utile.
Problem No. 3, the present one, has many parameters, including that:
due to the daily, west-to-east rotation of the earth about its polar axis, the sun apparently travels across the sky from sunrise in the east to sunset in the west, traversing an arc of 180.degree. from horizon to horizon; PA0 the polar axis of the earth is tipped from the vertical with respect to the plane of the orbit at an angle of about 23.degree.30', pointing continuously to Polaris, the North Star, and for this reason, as the earth revolves about the sun in its annual, nearly circular orbit, the sun also apparently travels up and down the sky in an annual cycle, through an arc of about 47.degree. north and south, the midpoints of this travel being the equinoxes, the extremes being the summer and winter solstices, the total cycle encompassing an arc of about 94.degree., and the average daily increment of this travel being about one quarter of a degree; PA0 at the equator on the day of an equinox the sun rises nearly due east, stands at the zenith at noon and sets nearly due west; at other latitudes on this day the sunrise and sunset headings are respectively the same as they are at the equator, but the meridian declination of the sun is south of the local zenith at north latitudes and north of the local zenith at south latitudes, the angle of declination in each case being equal to the latitude, and the variation in declination, from one latitude to another, being a function of the curvature of the earth; PA0 on the day of the summer solstice the sun rises a very small fraction of a degree less than 23.degree.30' north of east, has a meridian declination 23.degree.30' north of the equatorial zenith (assuming this to be the precise figure) and sets a very small fraction less than 23.degree.30' north of west, the angle being very nearly the same all day; PA0 the sunrise-to-sunset motion is repetitive, with a nocturnal return swing; the seasonal motion is oscillatory in an annual cycle, with small, progressive (except at the solstices, which are turn-around points) increments during each day and from one day to the next; PA0 a reflector, to follow the sun, must have a compound motion about a point, the point being on or geometrically within a heat receiver, and the motion being counter to the vectorial sum of the solar motions above described; PA0 the intensity of light is known to vary inversely as the square of the distance from source to object; the intensity of heat is said to vary inversely as the cube of the distance from source to object, although I have seen no scientific proof of this; but in either case an inverse ratio applies to the effect of distance from reflector to heat receiver; PA0 a moving reflector having a paraboloidal shape and contour is well known to the prior art (and very well known, in the opposite application, in millions of automobile headlights); due to the minimum effect of the inverse factor of distance the reflecting efficiency of this element is high, and the size and therefore the capacity of this element is limited only by the problem of bracing the structure against wind force; PA0 a plurality of plane mirrors, all moving to reflect sunbeams to a fixed heat receiver, is also known; the reflecting efficiency of this combination is lower than that of the above element, but, while the size of such an array is limited by the law of diminishing returns as it relates to the inverse factor of distance, the total reflecting area of the mirrors can be many times larger than that of the moving, paraboloidal reflector; PA0 the combination of a large array of moving, plane mirrors and a fixed, paraboloidal reflector, focused on a fixed heat receiver, is also known; while this combination is the most adversely affected by the inverse factor of distance, involving as it does two distances traveled by the reflected beams, it is still capable of producing the highest temperatures at the focal point, as witness the magnificent solar furnace at Odeillo, France, the acme of the prior art; PA0 a single configuration of a paraboloidal reflector and a motion-imparting mechanism--herein called a carriage--moving about a fixed, vertical axis and about a second axis which rotates in a horizontal plane, the two axes intersecting within a fixed heat receiver, can follow the sun at any latitude, but the motion, intended to include compensation for the latitude vector in meridian declinations, comprises redundant increments which render it inefficient; PA0 a single configuration of paraboloidal reflector and carriage having reflector motion about a fixed axis parallel to the polar axis of the earth and about a second axis which rotates in a plane parallel to the equatorial plane of the earth can follow the sun in true solar countermotion, which is 100% efficient, at any latitude, provided that the carriage be mounted on a base having an upper surface which is parallel to the polar axis, the base being static but varying in configuration from one latitude to another; PA0 a heat receiver which comprises a spherical boiler chamber containing a circulating, volatile fluid and is operatively connected to a heat engine is known to the prior art; it has been generally accepted practice to support both of these elements in fixed positions, as they are essentially power plant elements; PA0 a heat receiver lacking the cooling effect of the circulating medium is not recommended, due to the intense concentration of heat at the focal point of the paraboloidal reflector; PA0 the area efficiency of a reflector is diminished by shadow, a fact which has been neglected in the prior art, as the writer learned in the course of a comprehensive patent search; PA0 in the known structure which operates on vertical and horizontal axes the extent of a shadow which passes across the moving reflector varies from one latitude to another; PA0 in the new structure which operates on polar and equatorial axes the extent of shadow across the moving reflector is the same at all latitudes, so that the shaded area can be minimized by the arrangement of stationary elements of the structure, and the reflector area which is unavoidably shaded can be omitted, leaving a portion of a paraboloid which has an area efficiency of 100%; PA0 an example of the combination of moving, plane mirrors and a fixed chamber containing a volatile fluid, recently built in southern California, is arranged with the chamber high in the air and an operatively connected heat engine at ground level, an arrangement which is the same as--or worse than--that of the notoriously inefficient steam locomotive, wherein the boiler was above the cylinders; PA0 a combination comprising a moving, fully circular paraboloid and a fixed boiler chamber, in addition to having the shadow problem associated with chamber supporting structure, presents a problem of heat loss in transmission of the heated fluid from the chamber past the rim of the reflector; and PA0 the combination herein set forth, comprising the fixed boiler chamber, the moving, partial paraboloid and the polar plane base, can utilize simple cantilever members of an independent power plant structure to support both the chamber and a heat engine, and, by the simple and well-known principle that heat rises, the engine can be positioned above the chamber to accomplish the upward transmission of heated fluid with a thermal efficiency which is as good as can be expected in the overall combination.
The present concept achieves 100% area efficiency of the reflector, maximum efficiency in reflection, 100% efficiency of reflector motion and maximum thermal efficiency in the heat transfer cycle, at any suitable site in the torrid and temperate zones of the earth. The reflecting efficiency of the paraboloid, associated with the effect of the inverse factor of distance, must be presumed to be known to the prior art, but the other features are novel, and it is stressed that in a solar energy concentrating device operational efficiency is paramount.
The combination of reflector and carriage can be mass produced to a single design, thus enjoying the maximum of cost efficiency in manufacture, and since the reflecting surface will be the most expensive item to produce and to maintain, it will contribute to the cost efficiency if the area of said surface which is not fully effective is omitted.
The polar plane base, which in any case will be built on site, can be tailored to the latitude of each site, using adjustable forms for poured concrete.
A large plurality of moderately sized solar energy concentrators, each one having a partial-paraboloidal reflector on the order of 36' in diameter, and connected in groups of ten or so, each group connected to an electrolytic cell, can be installed in each of the desert areas of the world. The sources of both energy and raw material are practically unlimited.